Abstract: A well pumping unit comprising a double acting hydraulic cylinder actuator supported on a mast above a wellhead and having a piston rod connected directly to the polish rod of an elongated subsurface pump rod string. A generally cylindrical annular counterweight is disposed around the mast and is interconnected with the cylinder actuator by flexible chains trained over crown sheaves and travelling sheaves connected to the upper piston rod offsetting the weight of the pump rod string and at least a portion of the weight of the fluid column in the well. The pumping unit is controlled by a hydraulic control system including a directional control valve and flow control valves for selectively controlling the strokes of the cylinder actuator. A hydraulic pressure load sensing system measures total load on the rod string and provides for automatic shutdown of the actuator if the fluid level in the well is pumped below a predetermined level.